PURPOSE: To study the hormones and the hormonal changes occuring in nematodes during the process of aging. APPROACH: Five types of hormones will be studied in two species of free living nematodes: cyclic nucleotides, prostaglandins, steroidal hormones, juvenile hormone and serotonin. Experiments are described for the detection of each of the hormonal types and for demonstration of their formation by the nematodes. Changes in hormone levels prior to, during, and after ecdysis will be examined in an effort to learn more about the hormonal changes important to this process in nematodes. Changes in hormone levels and of key enzymes in hormone production will be studied in L2, L3, L4 larvae and in young and old adults. This may lead to an understanding of the hormonal systems of importance in aging in these organisms.